1. Field of the Invention
This invention relates to alternating current (AC) light emitting assemblies and AC light emitting devices, and more particularly, to an AC light emitting assembly and an AC light emitting device having the AC light emitting assembly, the AC light emitting assembly having a rectifier component for rectifying an AC signal into a direct current (DC) signal, the rectifier component having a high breakdown voltage and a low forward voltage.
2. Description of Related Art
With the rapid development of opto-electronics technology, light emitting diode (LED) has becoming one of the most popular light emitting components in the market and has been applied to varieties of electronic fields. In particular, alternating current (AC) LED has been proclaimed by Seoul Semiconductor Co. and III-N Technology Co. in a product announcement symposium to be a global product in the near future.
When receiving an AV signal, an AC LED emits light only during the positive half cycle of the AC signal. A Wheatstone Bridge is introduced to solve such the problem. In result, more than one half of a plurality of AC LEDs arranged in the Wheatstone Bridge emit light every half cycle of the AC signal.
Further, the adoption of an AC LED as a rectifier component in the Wheatstone Bridge introduces two drawbacks. One is that the Wheatstone Bridge has to comprises many rectifier components because the rectifier components have a low breakdown voltage. Practically, each of the four arms of the Wheatstone Bridge has to be provided with two or more than two rectifier components. If receiving an 110 volt AC signal, the Wheatstone Bridge requires as many as 40 rectifier components, 20 of which are installed in a positive path where a positive half cycle of the 110 volt AC signal passes, and the other 20 of the which are installed in a negative path where a negative half cycle of the 110 volt AC signal passes, such that the Wheatstone Bridge is robust enough to survive from a breakdown voltage induced from the 110 volt AC signal and having a peak value as high as 156 volts (110×√2). According to such a design, the Wheatstone bridge has only 110V/3.1V (an actuation voltage to actuate the AC LED)−20 (a number of AC LED for rectification)=15 AC LEDs capable of emitting light. In conclusion, the AC LEDs for rectification are far more than the AC LEDs for light emission, and the majority of input power will be consumed by the rectifier components and the Wheatstone Bridge has a low overall efficiency. The other one of the drawbacks is that the Wheatstone Bridge, though having a larger light emitting area compared to the prior art, still have many rectifier components do not emit any light during a reverse biased voltage, and has a significant portion of the light emitting area wasted.
Therefore, how to provide a design, even comprising few rectifier components, able to survive the reverse biased voltage applied by the AC signal has becoming one of the most urgent errands in the art.